Oil burner turbulator end cone, and method for generating counter-rotating air flow patterns

ABSTRACT

A gun type oil burner tip having a series of orifices or nozzles annularly arranged in pairs on the end of the gun in such manner that each nozzle pair projects an air stream, the respective nozzles in each pair being in close juxtaposition such that the projected air streams cross or intersect each other immediately forward of the nozzle such as to intertwine and define an expanding, rotating cone of gases comprised of discrete swirling streams having turbulent areas there between.

United States Patent Flournoy Dec. 2, 1975 1 OIL BURNER TURBULATOR ENDCONE, [56] References Cited AND METHOD FOR GENERATING UNITED STATESPATENTS COUNTER-ROTATING AIR FLOW 2,500,787 3/1950 Lelgemann 239/4025PATTERNS Inventor: Norman E. Flournoy, Richmond,

Assignee: Texaco Inc., New York, NY.

Filed: Dec. 1, 1972 Appl. No.: 311,199

Related US. Application Data Continuation-impart of Ser. No. 93,347,Nov. 27, 1970, abandoned.

US. Cl 239/402.5; 239/420 Int. C13... 3053 7/10; F23D 11/16 Field ofSearch 239/402.5406;

Primary Examiner-Lloyd L. King Attorney, Agent, or Firm-T. H. Whaley; C.G. Ries; Robert B. Burns [57] ABSTRACT A gun type oil burner tip havinga series of orifices or nozzles annularly arranged in pairs on the endof the gun in such manner that each nozzle pair projects an air stream,the respective nozzles in each pair being in close juxtaposition suchthat the projected air streams cross or intersect each other immediatelyforward of the nozzle such as to intertwine and define an expanding,rotating cone of gases comprised of discrete swirling streams havingturbulent areas there between.

7 Claims, 3 Drawing Figures US. Patent Dec. 2, 1975 Sheet 1 of2 3323,25

US. atent Dec. 2, 1975 Sheet 2 of2 3,923,251

OIL BURNER TURBULATOR END CONE, AND METHOD FOR GENERATINGCOUNTER-ROTATING AIR FLOW PATTERNS This is a continuation-in-partapplication of my original application Ser. No. 93,347, filed on Nov.27, i970 now abandoned.

The present invention relates to an oil burner and particularly to thearrangement of the flame producing elements of the oil burner to improvethe operation thereof, and to reduce the amount of smoke produced.

In particular, the invention relates to the type of oilburnerconventionally used for home and commercial operations. In such burnersa spraynozzle andignition means are arranged in a blast tube whichconducts a blast of air. The air blast or draft, as well as the sourceof power for the ignition device and the supply of fuel oil to the sprayhead, being created and supported by pumps, blowers and other means,form no part of this invention.

It further relates to a method for promoting a cleaner and moreefficient combustion of an air-fuel mixture. The method includes theintroduction of atomized fuel flow into the center of an oil burner.Simultaneously, a swirling cone formed of discrete air streams isintroduced to surround the fuel flow. Said discrete streams are formedby a series of air nozzle pairs so arranged to form jets of air whichintersect with a swirling mass.

In accordance with the present invention the blast tube of the burner isprovided with an exit or end cap or cone having a central chamber whichreceives the burner spray head. Around the'periphery of this chamber onthe cap or cone which covers the blast tube are two annular rows ofnozzles or exit tubes or openings, which function as orifices for theair blast or draft.

The exit tubes or orifices are set in two annular belts coaxially of theburner tube. Said tubes are spaced radially, or respectively so directedas to emit radially spaced jets of air. One annular belt comprises tubesor orifices which are aimed downstream at an acute angle to the tangentof the annular belt. Each of said orifices is set in approximately thesame annular direction, and slightly downstream. Stated otherwise, saidtubes are so directed that each jet of air from this annular belt oforifices is emitted tangetially or annularly in a common rotationaldirection and slightly downstream.

The other or second annular belt of orifices or tubes is aimed annularlyat an angle which is also slightly downstream but, however, in theopposite rotational direction.

The orifices or tubes of each annular belt are-radially indexed to causethe jet of air issuing from a tube of one annular belt to be directedobliquely across and adjacent to the path of air issuing from a wheatthe other annular belt. Thus, each orifice tube of one annular belt isarranged to pair in juxtaposition with the adjacent or correspondingorifice of the other annular belt. The air issuing forth from theseorifice pairs expands in a swirling stream. The resulting frictionalinteraction at the edges of the two swirling streams of aircreates ahigh level ofturbulence and shear. Each pair of orificesthereby sets upa rotational sheath or cone of air flow or air blast which rotates inthe same direction as the adjacent orifice pair form. Thus, the marginalcontact between adjacent pairs induces substantial additionalturbulence.

Into this region of turbulence a fine spray from the burner nozzle orspray head is directed so that intermixing ofthe fuel with air in theturbulent area is highly efficient and complete. The result is that ahigh degree of combustion is achieved.

Referring now to the figures of the drawing. there is shown a specificexample of a burner embodying the present invention.

In the drawings FIG. 1 illustrates a perspective detail of the extremityof the blast tube of a burner constructed in accordance with the presentinvention. A broken away portion of the combustion chamber is alsoshown.

FIG. 2 is an elevational view, taken diametrically from the left handextremity of the burner as shown in FIG. 1.

FIG. 3 is a vertical sectional elevation taken centrally thru theburner. 1

It is noted that in the present embodiment, conventional details of theburner, such as the arrangement of the air pump or blower and itsmetering device, the oil pump, and the bulk of the electrical equipmentand controls have been omitted for the reason that, per se, they are nota part of the present invention.

Suffice to say that the air blast is delivered via blast tube 10 whichis associated in a known manner with the blowers, pumps, controls, etc.

The present invention has to do mainly with the extremity or tip 12 ofthe blast tube, sometimes referred to as an end cone.

As shown more clearly in H68. 2 and 3, cone 12 is provided with acentral, axially extending cylindrical chamber 14 which accommodates thefuel spray head or nozzle 16. The latter, in turn, is supplied with fuelfrom pipe conduit 18. Bracket 20, supported on conduit 18, carries oneor more insulators 22 which, in turn, carry electrode or electrodes 24.

Apart from the fact that aperture or apertures 26 are provided toaccommodate insulators for the ends of electrodes 24, the interior ofthe nozzle chamber 14 is not otherwise in communication with theinterior of tube 10 except by means of an annular row of small apertures27. The latter pass constricted air streams which function to cool thefuel nozzle, and to blow the spark to a suitable position for goodignition characteristics.

Tube 10, by virtue of a continuous supply of air under pressure from afan or blower not shown, is

end wall 28 of the burner tip or end cone 12.

The air flow pattern which characterizes the present invention iscreated by nozzles or orifices 30 and 32. ln the present embodiment,said orifices comprise short lengths of tubing welded to the end face 28of the burner cone as shown.

A significant and essential feature of nozzles 30 and 32 is that theyare arranged such that adjacent pairs function together. Thus, airstreams, or jets. passing from each nozzle of a pair, intertwine toestablish a swirling, expanding flow. Said flows rotate in the samedirection as adjacent pairs thereby inducing substantial turbulence atthe point of tangency.

To establish the desired turbulent area, at least two, and preferably aplurality of said nozzle pairs are provided. As shown, the, presentarrangement provides for four pairs of cooperating nozzles equi-spacedabout tip 12. Tubes 30 are set in an annular pattern upon axes whichface in the same annular direction but which 3 make an acute angle in adownstream direction with a plane normal to the axis of the tube 10.

The second annular row of tubes 32, on the other hand, is identicallyarranged but in an opposite rotational direction.

The respective orifices or tubes of each annular belt are radiallyindexed to cause the jet of air issuing from a tube of one annular beltto be directed obliquely across, and closely adjacent to the jet of airissuing from a tube of the other annular belt. Thus, each jet of oneannular belt is arranged to pair with the adjacent jet of the otherannular belt. Air streams issuing from these jet pairs intertwine,expand, and swirl. The interaction of two adjacent streams of swirlingair creates a high level of turbulence and shear along the contactingmargins thereof.

In effect, the net result is dual air flows consisting of rotating,expanding streams of air. Preferably from the nature of this arrangementthese rotational, annularly spaced streams or sheathes of air tend toexpand and be conically disposed.

Therefore, at the interface or margins between the adjacent rotatingcones, a zone 34 is established (as shown in FIG. 2) where a shearingaction takes place between the oppositely moving streams. In thissection, a high degree of turbulence is generated. It is into this areathat spray nozzle 16 projects the highly atomized fuel oil.

Thus, as shown in FIG. 3, nozzle 16 projects, in the typical operation,a hollow, spray pattern of atomized fuel oil indicated by the referencenumeral 36. As indicated, the spray pattern is typically conical inshape, emerging from the tip of the nozzle as at 38 and expandingoutwardly therefrom. At the turbulent interface 34 the atomized sprayparticles enter the turbulent section. Due to the high degree ofshearing action, the fuel particles are further reduced thereby toeffect a more ideal intermixture for combustion.

As a result of the excellent mixing characteristic of the stream, veryclean combustion takes place. Actually, tests on this equipment haveshown that zero smoke formation is readily maintainable at excess airfigures as low as percent.

By way of example, parallel tests were run using a standard orconventional, widely distributed type of home oil burner.

The zero smoke number of this conventional burner was determined at anexcess air value of 45 percent. Then, the end member of the burner(referred to as the star), and the internal air turbulator (referred toas the lily). were removed and replaced by the end cone shown anddescribed above. A high speed motor (3,450 rpm) replaced the standard(1,725 rpm) motor and therefore drove the standard blower to produce ahigher than normal pressure in the burner plenum.

This modified, standard burner was then retested to determine its smokenumber, starting with high excess air values. Since the smoke number waszero at all air values comparable with that of the original burner, theamount of excess air was lowered to 15 percent to produce the followingcomparative results.

-continued Excess Air Smoke Number It is apparent from the tabulation,that the present invention contributes measurably to the attainment ofimproved efficiency and clean combustion products without the need forgreat amounts of excess air.

The resultant pattern of gas flow from burner tip 12 thus takes a formwhich is illustrated more specifically in the figures of. the drawing.For example, FIG. 1 shows, in segregated form, the action of the gasstreams flowing from one pair of cooperating burner orifices or nozzles30 and 32.

After issuing from the respective nozzles, the two streams obviously andtypically expand to some extent. However, and suprisingly, being inclose juxtaposition at the point where the crossing jets or streams ofgas tend to contact or interact, they commence to spiral on one anotheras clearly shown in the figure. As a result, a spiral expanding cone ofgas in which the shearing and turbulence reach a high degree of activitythus results.

While FIG. 1, for purposes of clarity, illustrates the cooperativeaction of only one pair of jet nozzles in creating a spiral, rotary,expanding cone of gas, it will be apparent that each pair of nozzles ororifices operates in the same manner. As a result therefore, the fourrespective pairs of nozzles continuously set up four, annularly spaced,cones of expanding, spirally intertwined gases, as clearly shown in anend view of FIG. 2.

In fact, such an action is apparent to the naked eye in the operation ofthis device.

FIG. 3 also illustrates by arrows, the areas of frictional interactionor turbulence which tend to be set up along the margin between therespective cones of gas. Not only does each cone operate in essentiallythe same rotational direction, that is to say in a counter clockwisedirection as viewed in FIG. 2, but between each expanding cone of gasthere are ultimately set up opposite interactions of shear between thetwo cones.

Further, in this connection, it is noted that due to the severalrotational actions set up, the entire interior atmosphere of thefurnace, namely the gaseous products issuing from the respective pairsof nozzles (and including gaseous products of combustion) all rotatelikewise in a counter clockwise direction.

The result therefore is a novel operation, the basic characteristics ofwhich are usually apparent to the naked eye and, as evident from theaforementioned example. Further, the resulting flame is blue in color, acharacteristic of clean, efficient combustion as a result of the highdegree of intermixing.

I claim:

1. In an oil burner comprising an elongated air blast tube having acentral axis with opposed inlet and dis= charge ends, said tube beingcommunicated with a source of pressurizing air, a fuel nozzle tip andignition means in said tube to ignite an air=fuel mixture, the lm=provement in said oil burner which comprises;

a cap carried on the inlet end of said air blast tube, said cap beingprovided with orifice means com= prising at least two pairs of closelyspaced orifices, each orifice being communicated with a source of air,said at least two orifice pairs being spaced an= nularly from each otherabout said blast tube central axis,

each orifice opening in the respective orifice pairs having alongitudinal axis directed to form an angle with a plane passing normalto said blast tube central axis, the longitudinal axes of saidrespective orifice openings being further biased toward each other,

whereby adjacent streams of air issuing from adjacent orifice pairs areswirled in a common rotational direction to interact and mutually form arotatably expanding, conically shaped air stream along said air blasttube, and flowing toward the discharge end of the latter,

the respective swirling air streams from each orifice pair being spacedabout said blast tube central axis to define therebetween an area ofhigh turbulence and shear along the inner margin. of the conicallyshaped air stream into which atomized fuel is introduced.

2. In an apparatus as defined in claim 1, wherein the respectiveorifices are substantially equivalent in opening to deliversubstantially equivalent volumes of air.

3. In an apparatus as defined in claim 1, wherein each pair of orificesis arranged with respect to adjacent orifice pairs, whereby to form aswirling stream which rotates in the same direction as the adjacentswirling stream.

4. In an oil burner as defined in claim 1 wherein the respective airorifices axes pairs are directed in nonintersecting disposition.

5. In an oil burner as defined in claim 1 wherein said plurality oforifices are spaced annularly equidistant apart about said cap.

6. In an oil burner as defined in claim 1 wherein said plurality of airorifices are spaced radially equidistant from the center of said cap.

7. In an oil burner as defined in claim 1 wherein at least four orificepairs are spaced annularly equidistant about said cap.

1. In an oil burner comprising an elongated air blast tube having acentral axis with opposed inlet and discharge ends, said tube beingcommunicated with a source of pressurizing air, a fuel nozzle tip andignition means in said tube to ignite an air-fuel mixture, theimprovement in said oil burner which comprises; a cap carried on theinlet end of said air blast tube, said cap being provided with orificemeans comprising at least two pairs of closely spaced orifices, eachorifice being communicated with a source of air, said at least twoorifice pairs being spaced annularly from each other about said blasttube central axis, each orifice opening in the respective orifice pairshaving a longitudinal axis directed to form an angle with a planepassing normal to said blast tube central axis, the longitudinal axes ofsaid respective orifice openings being further biased toward each other,whereby adjacent streams of air issuing from adjacent orifice pairs areswirled in a common rotational direction to interact and mutually form arotatably expanding, conically shaped air stream along said air blasttube, and flowing toward the discharge end of the latter, the respectiveswirling air streams from each orifice pair being spaced about saidblast tube central axis to define therebetween an area of highturbulence and shear along the inner margin of the conically shaped airstream into which atomized fuel is introduced.
 2. In an apparatus asdefined in claim 1, wherein the respective orifices are substantiallyequivalent in opening to deliver substantially equivalent volumes ofair.
 3. In an apparatus as defined in claim 1, wherein each pair oforifices is arranged with respect to adjacent orifice pairs, whereby toform a swirling stream which rotates in the same direction as theadjacent swirling stream.
 4. In an oil burner as defined in claim 1wherein the respective air orifices axes pairs are directed innon-intersecting disposition.
 5. In an oil burner as defined in claim 1wherein said plurality of orifices are spaced annularly equidistantapart about said cap.
 6. In an oil burner as defined in claim 1 whereinsaid plurality of air orifices are spaced radially equidistant from thecenter of said cap.
 7. In an oil burner as defined in claim 1 wherein atleast four orifice pairs are spaced annularly equidistant about saidcap.